Indole-, imidazole- and phenyl-alkylamines in the skin of one hundred amphibian species from Australia and Papua New Guinea

Abstract

1. Extracts prepared from the dried skins of approximately one hundred amphibian species from Australia and Papua Guinea were subjected to chemical and biological screening in order to determine the nature and amounts of biogenic amines in their skins. 2. The most frequently and abundantly occuring amines were indolealkylamines, represented by their prototype 5-HT, by the entire series of N-methylated derivatives of 5-HT (N′-methyl-5-HT, N′,N′-dimethyl-5-HT or bufotenine, bufotenidine) and by some new compounds: O-sulphate of bufotenine, O-sulphate of bufotenidine and the quaternary ammonium derivative of tryptamine. 3. Imidazolealkylamines were usually represented by histamine, N′-accetyl-histamine, N′-methylated histamines (N′-methylhistamine, N′,N′-dimethylhistamine) and cyclized histamines (spinaceamine, 6-mehtylspinaceamine) could be detected only in the skins of a limited number of species. 4. The above spectra of indole- an imidazolealkylamines are destined to broaden, because several other indole and imidazole derivatives in skin extracts have been identified and partly characetrized by paper chromatography and electrophoresis. 5. The importance of amphibian skin as a rich source of biogenic amines, and their precursors and metabolites, is emphasized.